Viscose spinning process and apparatus



June28, 1955 A. H. LYNCH ETAL VISCOSE SPINNING PROCESS AND APPARATUS Filed June 28, 1952 INVENTORS.

ADDISON H. LYNCH WILLIAM B. MILLER 2,711,559 vrscosn SPINNING PROCESS AND APPARATUS Addison HQL neh and William B. Miller, Rome, Ga., assignors to Celanese Corporation of America, New York, N. Y., a corporation of Delaware Application June 28,1952, Serial No. 296,204

' 12 Claims. (01. 18-8) This invention relates to the spinning of viscose and relates more particularly to a novel process and apparat-us for the production of regenerated cellulose artificial filamentary materials by the viscose process.

In the production of regenerated cellulose artificial filamentary materials by the viscose process, viscose is pumped orotherwise forced through a spinnerette con taining one or more spinning apertures therein into a liquid spin bath which causes the filamentary materials to set. The filamentary materials are then drawn through and from the spin bath and may be treated in any of a large number of ways known in the art to obtain products having certain desired properties. The spinning opertaion itself, i. e. the extrusion of the viscose into the spin bath and the passage of the filamentary materials through the spin bath, tends to introduce certain irregularities into the filamentary materials which are evidenced, for example, by a non-uniform dyeing of the filamentary materials. The normal spinning operation also tends to limit the maximum elongation that can be obtained in the final products. In addition, the maximum speed of the filamentary materials in the spinning operation must be kept at a relatively low value to avoid the production of products having undesirable properties. The relatively low spinning speed curtails the productive capacity of the spinning equipment.

It is an important object of this invention to provide a process and apparatus for the production of regenerated cellulose artificial filamentary materials by the viscose process which will be free from the foregoing and other difiiculties and which will be especially eificient in operation and simple in construction.

A further object of this invention is to provide a process and apparatus for the production of artificial filamentary materials by the viscose process which will yield products having more uniform properties.

Another object of this invention is to provide a process and apparatus for the production of artificial filamentary materials by the viscose process which will yield products having a relatively high elongation.

A still further object of this invention is to provide a process and apparatus for the production of artificial filamentary materials by the viscose process which may be operated at relatively high spinning speeds.

Other objects of the invention, together with certain details of construction and combinations of parts, will be apparent from the following detailed description and claims. i

According to the present invention, there is provided an apparatus for the production of artificial filamentary materials by theviscose process in which a spinnerette, having at least one spinning aperture therein, is positioned in a spin bath. Extending upwardly from the spinnerette to a point above the surface of the spin bath is a conduit through which the artificial filamentary materials pass as they emerge from the spin bath. The conduit is open to the spin bath, preferably at one or more points adjacent to the spinnerette, so that the spin bath will flow into the conduit. As the filamentary matates Patent 2,711,559 Patented June 28, 1955 terials pass through the conduit they will induce a flow of the spin bath through the conduit in the same direction as the movement of the filamentary materials. Positioned at a point above the surface of the spin bath is means for removing from the filamentary materials the major portion of the spin bath flowing along therewith. This latter means is positioned so that the filamentary materials will reach said means before the major quantity of the spin bath flowing along with the fila- 'icc mentary materials falls away from the filamentary ma-- terials freely under the force of gravity. In this way,

the point at which the spin bath flowing along with the filamentary materials is removed from said filamentary materials is fixed or predetermined.

The conduit forming the passageway through which the filamentary materials pass as they emerge from the spinning apertures in the spinnerette may advantageously be provided at its end adjacent the spinnerette with an' enlarged portion of generally conical shape. Best results are obtained when the enlarged portion is between about /2 and 3 /2 inches long measured from the face of the spinnerette to its point of minimum diameter.

face of the spinnerette and serves to direct the flow of the spin bath through the conduit where the freshly formed filamentary materials first contact the spin bath,

and, in combination with the small diameter portion of the conduit, to limit the tensions imposed on said freshly formed filamentary materials. The total length of the conduit may be varied over a considerable range, good results having been obtained with conduits having a length of between about 13 and 16 inches measured from the face of the spinnerette. While the diameter of the conduit may be varied considerably, the best results are obtained when the diameter of the conduit is kept within relatively narrow limits. It has been found that as the diameter of the conduit is varied, keeping all other conditions, such as spinning speed, number of filaments, conduit length and the like unchanged, the rate of flow of j the spin bath will pass through a maximum at one particular diameter. The rate of flow of the spin bath through the conduit will drop both with conduits having a larger diameter or a smaller diameter. The best results are obtained when the diameter of the conduit is within about 40% of the diameter at which the maxi-. mum rate of flow of the spin bath is obtained, preferably below the point of maximum flow. While the conduit may be inclined at a considerable angle to the vertical,

it is preferred to have the conduit positioned generally vertically.

The distance which the top of the conduit projects above the surface of the spin bath, which distance represents the hydrostatic head against which the filamentary materials must raise the spin bath, should preferably be kept short. In general, this distance should not exceed about 6 inches or preferably about 2 inches to obtain products having the most desirable properties.

One or more openings are provided to permit access of the spin bath to the interior of the conduit. These openings are advantageously arranged so that the spin bath will be moving smoothly in the same direction as rials the major portion of the spin bath fl owing along.

The enlarged portion of the conduit completely encircles the therewith may comprise a member positionedso as to contact the filamentary materials physically. For example, this member may comprise a roll which may be ffeeto rotate or which may be positively driven at a suitable speed: Alternatively, the ma or portion of the Split ba'tl'i flowing along with the filamentary materials may be removed therefrom by providing the conduit with one or more openings ini'ts side throughwhichthe spin" bath will be discharged; Filamentary materials produced with an apparatus employing a conduit provided witli-a discharge opening for removing the spin bath from the filamentary materialshave a higher elongation so that this" apparatus is somewhat more desirable; In all cases, the means for removing from the filamentary ma te'ria'ls the major portion of the spinbat'h flowing along falling" away occurs will fluctuate thereby introducing irregularities into the filamentary materials which will be evidenced, for example, by a non-uniform dyeing of the filamentary materials.

The filamentary materials produced employing the process and apparatus of this invention have a higher elongation than filamentary materials produced under similar conditions when no conduit is provided through which thefilamentary materials pass. When it is desired to obtain products having a reduced elongation, the filamentary materials emerging from the spin bath may be placed under a considerable tension to stretch the same which will simultaneously increase their tenacity" and lower their elongation. Through the use of this expedient, the flexibility of the process is greatly increased since it' is possible to obtain products having diiferen't elonga'tion's simply by changingthe degree of stretch imparted" to the filamentary materialsl The use of this expedient also increases the productivity of the apparatus since the' take-up speed and production rate of the filame'ntary' materials will be increased by a percentage equal" to the percentage stretch imparted to the filamentary materials.

The process-and apparatus of this invention also permit the use of relatively high spinning speeds. When attempts aremade to increase the spinning speed employ'ing" conventional apparatus, the properties of the filamentary materials becomeunsatisfactory for commercial use. According to the present invention, the spinning-speedsmay-be increased byasmuch as 25%, or even more while obtaining products that are eminently satisfactory. This increase inspinning speed producesa like increase in the productive capacity of the apparatus:

The. filamentary materials obtained in accordance with this. invention-are substantially more uniform as evi denced, forexample, byamore uniform dyeing, Fabrics and the like produced from these filamentary materials may accordingly be finished to more exacting standards thanis possiblewith fabrics produced from filamentary materials having less uniform properties:

Preferredernbodirnents of this invention are shown in theaccompanying drawings wherein:

Fig. 1 is a front elevationalview, partly insection; of one form of apparatus,

Fig. ZTis a cross-sectionalview, onan-enlargedscale, taken'onv the line 2-2 in Fig. l in" the directionof the" arrows,

3 is-across-sectional view, on an=enlargedscale',- taken'on. the line 3-'3-in Fig. 2in'the directionof the arrows,

Fig; 41 is .-across-sectional' view'taken on' the line" 4 4"- in Fig; 1 in'the direction of' the arrows,

Fig. 5 isa detail view, on an enlarged scale, showing the Cit Referring now to the drawing, the reference numeral 11 designates a tank or trough for holding a suitable spin bath 12 in which is positioned a spinning assembly indicated generally by the reference numeral 13. The spinning assembly 13 comprises a conduit 14 through which viscose is pumped to a spinning head 15 seated in a supporting member 16 and carryinga spinnerette 17. The viscose emerges"- frorn the s'pinnerette 17 as a bundle of filaments 18. Extending upwardly from the spinning head 15' that poistgtmye the upper level of the spin bath 12 is a conduit 19 whose lower end 21 is of generally conical shape and completely encircles the spinnerette 17. The lower end of the conduit 19' is provided internally with a plurality of ridges 22 which bear against the spinning head 15 and act to hold the lower end of the conduit 19 spaced from said spinning head to permit free access of the spin bath into the conduit 19. Adjacent its upper end, the conduit 19 is slidably supported in a mount 23' carried by a bracket 24 As the filaments 18" pass through the conduit 19 they will iiiduce a'fiow of spin bath through the said conduit. The" filaments 18 remain substantially parallel and doubt tend to contact one another during' their passage through the conduit ,19 so that the spinbath will'h'a've free access toeach filament and the treatment of each filament will be substantially identical.

After emerging from the conduit 19; the filaments 18 pass f over an idiot roller 25"rotat a bly; supported on' a stub shaft 26 carried by a dovetail, 27 whichis mounted in a bracket 23. The idler rolier positioned with respect to the end of the conduit 19 sothfat" the filaments 18 will reach said idler roller before the major portion of the spin bath fiowin'galongtherewith will fall' away from thefilaments 1 8 freely under the force of gravity. In this Way, the idler roller 25 will fix' tl'le poi'nt at which the major portion of the spin bath flowing along there'- with is removed fromthe'filaments Following their passage over the idler' roller 25, the filaments 18 pass under a second idler roller 29 rotatably supported on a stub'shaftlal mounted onthebracket 28, in such a manner that said ro'ller 2Q'is-above thelevel of the spin bath' 12. Thefilaments18next a s's -arc iund agodet wheel'h32, driven in anysuitable manner (not'show'n), and a skewed idler roller 33; and: are theii'tak'en' up on a bobbin 34, driven in any suitable manner-pm shown), onto which they are directed by mea'ris of a'recipr'ocating guide 35.

By adjustingthe]relative 'sjgieeds of the godet' wheel 32' and the bobbin 34; anyjdesireddegree'of stretch may be imparted to the filaments 18f V v The conduit 19'lias'fixed thereto a number of pro: jections'36; When accessis"desir'ed'to the spinning" head 15 or spinne're'tt e 17, for example, at' th'e start of the spinning operation; the idler roller25fis're'moved by liftin'gent the several-27 annthe cbhd it 19 instead until the projectionslit'ia're ata'higherlevel than a ledge 37 extending from the braeketQZ i', as shownin deadlines in Fig. 1 of the drawing; Theconduit 19 is then rotated through a small'a'rigle to bring oneof the projections 36 above the led'g'e37, as shown injd'o'tt ed: lines in" Fig. 4 of the drawing; so tha't'the"conduitf'19will be supported in its raised position otfsaid ledge 37. To lower'thecon duit'19to'its'operatingposition, the procedure'is reversed, the conduit 19 being tiirn'ed through a small angle until the projections 36 will clear theledge 37, as shown in full lines in Fig. 4 of thedrawing, following which the conduit' l9 is lowered untilthe ridges 2'2'rest against the spinning'head15; r l N Fig. 6 shows one type of a modifiedform of apparatusinwhich there is fixe dto'; the'upper end of the con"- duit19, by means f adapting 38, a1 conduit 39having' an openin g 4'1 in itfs'side'througli which the spin bath;

flowing along with theffilaments, is discharged.- This modification produces filaments h'aving' a somewhat higher' elongation, apparently because the filaments" remain under a' lower and'more uniform tensionin the passage to the bdetwheel'sz.

Gr -a.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of our invention.

Having described our invention, what we desire to secure by Letters Patent is:

1. In the production of regenerated cellulose artificial filamentary material by the viscose process, the steps which comprise forcing viscose through a spinnerette into a body of spin bath in which the spinnerette is submerged, passing the freshly formed filamentary materials through a generally vertical conduit extending through the spin bath to a point above the surface of the spin bath and having a conical-shaped lower end encircling the spinnerette and freely open to the spin bath whereby the movement of the filamentary materials through the conduit will induce a smooth flow of spin bath free from turbulence through the conduit in the same direction as the movement of the filamentary materials and carry a stream of spin bath out of the conduit at a point above the level of the spin bath, the movement of the spin bath through the conduit being entirely the result of the drag of the filamentary materials on the said spin bath, said conduit having a diameter within about 40% of the diameter at which the maximum rate of flow of the spin bath through the conduit is obtained as the diameter of the conduit is varied while all other conditions remain constant, and removing from the filamentary materials the major portion of the spin bath flowing along therewith before said spin bath falls away from the filamentary materials freely under the influence of gravity whereby the point at which said removal takes place is fixed.

2. Process according to claim 1 wherein the conicalshaped portion of the conduit through which the filamentary materials first pass is between about /2 and 3% inches long measured from the face of the spinnerette.

3. Process according to claim 1 wherein the diameter of the conduit is less than that at which the maximum rate of flow of spin bath therethrough is obtained.

4. Process according to claim 1 wherein the conduit extends above the surface of the spin bath a distance of less than 6 inches.

5. Process according to claim 1 wherein the conicalshaped portion of the conduit through which the filamentary materials first pass is between about /2 and 3 /2 inches long measured from the face of the spinnerette, wherein the diameter of the conduit is less than that at which the maximum rate of flow of spin bath therethrough is obtained and wherein the conduit extends above the spin bath a distance of less than 2 inches.

6. Apparatus for the production of regenerated cellulose artificial filamentary materials by the viscose process, comprising means for holding a body of spin bath, a spinnerette submerged in said spin bath, a generally vertical conduit extending through the spin bath to a point above the surface of the spin bath and having a conical-shaped lower end encircling the spinnerette, all openings in said conduit below the level of said spin bath being freely open to the spin bath and all openings in said conduit above the surface of said spin bath being freely open to the atmosphere whereby the movement of the filamentary materials through the conduit will induce a smooth flow of spin bath free from turbulence through the conduit in the same direction as the movement of the filamentary materials and carry a stream of spin bath out of the conduit at a point above the level of the spin bath, the movement of the spin bath through the conduit being entirely the result of the drag of the filamentary materials on the said spin bath, said conduit having a diameter within about 40% of the diameter at which the maximum rate of flow of the spin bath through the con duit is obtained as the diameter of the conduit is varied while all other conditions remain constant, and means for removing from the filamentary materials the major portion of the spin bath flowing along therewith before said spin bath falls away from the filamentary materials freely under the influence of gravity whereby the point at which said removal takes place is fixed.

7. Apparatus according to claim 6 wherein the length of the conical-shaped portion of the conduit is between about /2 and 3 /2 inches.

8. Apparatus according to claim 6 wherein the diameter of the conduit is less than that at which the maximum rate of flow of spin bath therethrough is obtained.

9. Apparatus according to claim 6 wherein the conduit extends above the surface of the spin bath a distance of less than 6 inches.

10. Apparatus according to claim 6 including means slidably supporting said conduit whereby the conduit may be moved away from the spinnerette to provide access to the spinnerette.

11. Apparatus according to claim 10 including means for holding the conduit in a position spaced from the spinnerette.

12. Apparatus according to claim 11 wherein the length of the conical-shaped portion of the conduit is between about /2 and 3 /2 inches, wherein the diameter of the conduit is less than that at which the maximum rate of flow of spin bath therethrough is obtained, and wherein the conduit extends above the surface of the spin bath a distance of less than 2 inches.

References Cited in the file of this patent UNITED STATES PATENTS 2,054,852 Dreyfus Sept. 22, 1936 2,511,699 Drisch June 13, 1950 2,536,092 Roberts Jan. 2, 1951 2,659,102 Rarick Nov. 17, 1953 

6. APPARATUS FOR THE PRODUCTION OF REGENERATED CELLULOSE ARTIFICIAL FILAMENTARY MATERIALS BY THE VISCOSE PROCESS, COMPRISING MEANS FOR HOLDING A BODY OF SPIN BATH, A SPINNERETTE SUBMERGED IN SAID SPIN BATH, A GENERALLY VERTICAL CONDUIT EXTENDING THROUGH THE SPIN BATH TO A POINT ABOVE THE SURFACE OF THE SPIN BATH AND HAVING A CONICAL-SHAPED LOWER END ENCIRCLING THE SPINNERETTE, ALL OPENINGS IN SAID CONDUIT BELOW THE LEVEL OF SAID SPIN BATH BEING FREELY OPEN TO THE SPIN BATH AND ALL OPENINGS IN SAID CONDUIT ABOVE THE SURFACE OF SAID SPIN BATH BEING FREELY OPEN TO THE ATMOSPHERE WHEREBY THE MOVEMENT OF THE FILAMENTARY MATERIALS THROUGH THE CONDUIT WILL INDUCE A SMOOTH FLOW OF SPIN BATH FREE FROM TURBULENCE THROUGH THE CONDUIT IN THE SAME DIRECTION AS THE MOVEMENT OF THE FILAMENTARY MATERIALS AND CARRY A STEAM OF SPIN BATH OUT OF THE CONDUIT AT A POINT ABOVE THE LEVEL OF THE SPIN BATH, THE MOVEMENT OF THE SPIN BATH THROUGH THE CONDUIT BEING ENTIRELY THE RESULT OF THE DRAG OF THE FILAMENTARY MATERIALS ON THE SAID SPIN BATH, SAID CONDUIT HAVING A DIAMETER WITHIN ABOUT 40% OF THE DIAMETER AT WHICH THE MAXIMUM RATE OF FLOW OF THE SPIN BATH THROUGH THE CONDUIT IS OBTAINED AS THE DIAMETER OF THE CONDUIT IS VARIED WHILE ALL OTHER CONDITIONS REMAIN CONSTANT, AND MEANS FOR REMOVING FROM THE FILAMENTARY MATERIALS THE MAJOR PORTION OF THE SPIN BATH FLOWING ALONG THEREWITH BEFORE SAID SPIN BATH FALLS AWAY FROM THE FILAMENTARY MATERIALS FREELY UNDER THE INFLUENCE OF GRAVITY WHEREBY THE POINT AT WHICH SAID REMOVAL TAKES PLACE IS FIXED. 